The present invention relates to a directional control valve for compressed air, and in particular to a directional control valve which is mounted on an adapter plate and is of the type having a housing accommodating a control piston by which the connection between an inlet port, at least one consumer port and at least one vent port is controlled, wherein a one-way restrictor is arranged between the vent port and the consumer port.
In directional control valves of this type, in particular when being mounted on adaptor plates with common ventilation, the occurrence of dynamic pressures in the vent ports should not result in an undesired flow of fluid to the consumer or consumers and thus in undesired cylinder motions. Therefore, it is necessary to prevent a return flow of compressed air from the common ventilation to the consumer ports. Conventionally, such devices to prevent a return flow include an intermediate plate with a non-return valve (check valve) between the valve block and the adapter plate. These devices are, however, of great dimensions and expensive.